As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Examples of portable information handling systems include notebook computers, tablet computers and smart phones. These portable electronic devices are typically powered by rechargeable battery pack systems such as lithium ion (“Li-ion”) or nickel metal hydride (“NiMH”) battery packs. Such battery packs are typically equipped with a battery management unit (BMU) that monitors voltage or state of charge of the battery cells of the battery pack, and that controls flow of charge current to battery cells of the battery pack and flow of discharge current from the battery based on this monitored battery cell voltage. Such battery packs are also typically equipped with a fuse that is controlled by the BMU to permanently disable the battery pack from supplying current to the information handling system for a number of possible reasons, including if the monitored battery cell state of charge ever becomes low enough to damage the battery cells or if the monitored battery cell state of charge ever drops below a pre-determined permanent failure operating voltage or capacity threshold. In modern battery packs, when the battery cells reach such a critical low voltage or capacity threshold, a permanent failure (PF) flag is set, and the BMU will blow the fuse the next time external AC adapter power is present. This is done for safety reasons to prevent further operation of the information handling system at low battery charge levels which may be damaging to the battery cells and/or which may indicate a battery cell failure.
To avoid dropping below low cell voltage and/or to avoid overdischarge stress (and the resulting permanent disablement of the battery pack by the BMU) under normal battery pack operating conditions, the BMU and/or operating system (OS) of the typical information handling system shuts off or reduces current flow from the battery pack to the information handling system at a battery voltage level that is above the permanent failure operating voltage threshold. In the OS case, the OS monitors the current voltage of the battery pack battery cells that is reported to the OS by the BMU or receives an alert from the BMU when a pre-established threshold has been crossed. Either way, the BMU and/or OS react to the value of the monitored battery voltage level by individually shutting down power-consuming components (load) of the information handling system or by shutting down flow of current to the information handling system from the battery pack when the monitored battery voltage drops below a pre-determined minimum acceptable operating voltage threshold that is set above the pre-determined permanent failure operating voltage threshold. When current draw from the information handling system is shutdown in this manner, the charge level or voltage of the battery cells of the battery pack may recover under no load conditions to a voltage that is equal to or higher than the minimum acceptable operating voltage threshold. When this occurs, the OS and/or BMU will allow the power-consuming components of the information handling system to be restarted until the monitored battery voltage once again drops below the minimum acceptable operating voltage threshold, and further reducing the amount of voltage “cushion” above the absolute permanent failure operating voltage threshold at which the BMU permanently disables the battery pack.